1. Field Of The Invention
The present invention generally relates to an apparatus for preparing stitch position-related data utilized by an embroidery sewing machine, and particularly to the art of automating the operation of preparing stitch position-related data utilized by an embroidery sewing machine for embroidering a predetermined area by forming stitches at stitch positions and filling the area with the formed stitches.
2. Related Art Statement
One of the Applicants has filed a U.S. patent application Ser. No. 07/592,983, filed Oct. 4, 1990, in which he proposes an apparatus for automatically preparing stitch position-related data utilized by an embroidery sewing machine. The proposed apparatus includes (a) dividing means for dividing an area to be embroidered, into a plurality of sub-areas based on outline data representative of an outline of the area, the outline data including sets of position data each of which is representative of a corresponding one of specific positions specified on the outline, and (b) data producing means for producing the stitch position-related data based on the sub-areas. An area to be embroidered may be a polygon or a closed line approximated by a polygon, and the specific positions specified on the outline of the polygon as the area may be the vertices of the polygon. In the case where the outline of an area to be embroidered is approximated by a function such as a spline function, the outline data therefor may consist of sets of position data representative of points defined by the function. An area E shown in FIGS. 8, 19, and 32 is a polygon, and the specific positions specified on the outline of the polygon E are the vertices of the polygon, numbered one through thirty two.
A first example of the dividing means divides an area into divided areas as the sub-areas so that the outline of each of the divided areas has no outward deflection position thereon in an X-Y coordinate system provided for the outline. The deflection position on the outline in the X-Y coordinate system is defined as being a specific position at which the two specific positions adjacent to the specific position in question, respectively located on both sides thereof, are both located on one side of a straight line which passes the specific position in question and is perpendicular to a pre-selected one of the X and Y axes of the X-Y coordinate system. In the case where the specific positions are checked on the outline in a clockwise direction, the outward deflection position is defined as being a deflection position the following specific position of which is located on a left-hand side of the deflection position in question. On the other hand, in the case where the specific positions are checked in a counterclockwise direction, the outward deflection position is defined as being a deflection position the following specific position of which is located on a right-hand side of the deflection position in question. FIG. 18 shows an example of the division of an area into divided areas by the first example of the dividing means.
A second example of the dividing means includes determining means for determining the most distant, or approximately the most distant, two positions of the specific positions specified on the outline line of an area, and checking means for judging whether or not all straight segments obtained by connecting between each of the distant two positions and each of the remainder specific positions on the outline, are contained in the area. This dividing means divides the area into divided areas as the sub-areas so that the checking means provides an affirmative judgment for each of the divided areas. FIG. 19 shows an example of the division of an area into divided areas by the second example of the dividing means.
The division of a predetermined area into divided areas by the first or second example of the dividing means, is effected for the purpose of reducing the direction of a straight line approximating each of the divided areas (hereinafter, referred to as the longitudinal direction for the reason indicated later), to being generally parallel to the direction of a curved line or polygonal line approximating the same divided area which direction is taken at any position or portion on the line (hereinafter, referred to as the central-line direction). The second example of the dividing means may be operated for a divided area produced by the first example of the dividing means.
A third example of the dividing means includes first determining means for determining the most distant, or approximately the most distant, two positions of the specific positions specified on the outline line of an area, as a minimum and a maximum position of the area, second determining means for determining the direction of a straight line passing the minimum and maximum positions as a longitudinal direction of the area, the outline consisting of a pair of portions which are opposed to each other with respect to the minimum and maximum positions, third determining means for comparing the number of specific positions of one of the opposed portions of the outline, with that of the other portion thereof, and determining as a first portion of the outline one of the opposed portions which includes the smaller number of specific positions, defining means for defining a plurality of straight first aid lines which are perpendicular to the longitudinal direction and each of which passes a corresponding one of the specific positions of the first portion and intersects the second portion other than the first portion, the first aid lines dividing the area and the outline into blocks and segments, respectively, each of the blocks being enveloped by corresponding two of the first aid lines which are opposed to each other and corresponding two of the segments which are opposed to each other, and modifying means for modifying the each block by selecting, as a division base position, one of the specific positions of the second portion which one position cooperates with the specific position associated with each of the opposed two first aid lines of the each block to define, in place of the each first aid line, a corresponding one of division lines which passes the associated specific position belonging to the first portion and the division base position belonging to the second portion, the modified blocks serving as the sub-areas and including two triangle-like blocks each of which is approximated by a triangle defined by three specific positions and to which the minimum and maximum positions belong, respectively. The blocks except for the two triangle-like blocks are quadrangle-like blocks each approximated by a quadrangle defined by four specific positions. The blocks are produced from the area so as to provide an array extending generally in the longitudinal direction of the area. The third example of the dividing means may be operated for a divided area produced by the first and/or second example of the dividing means. FIG. 32 shows an example of the division of an area into blocks by the third example of the dividing means.
Three of the Applicants have also filed a Japanese Patent Application No. 1(1989)-167875 on Jul. 19, 1989, which has not been published. In the Application, they proposes an apparatus for automatically preparing stitch position-related data utilized by an embroidery sewing machine. The proposed apparatus includes data producing means for producing sets of sub-area data each of which is representative of an outline of a corresponding one of sub-areas of an area to be embroidered and, based on the sets of sub-area data, determining an order of embroidering of the sub-areas such that, when an embroidery sewing machine forms stitches with a continuous thread and fills each of the sub-areas by the formed stitches, by utilizing the sets of sub-area data and the order of embroidering of the sub-areas, the continuous thread does not pass over the stitches filling the each sub-area. In order to embroider an area with a continuous thread, first, a start and an end position at which embroidering or stitching starts and ends, respectively, are specified, and then stitches are formed from the start position to the end position for filling the area with the formed stitches. In the case where an area to be embroidered has no junction or branch like a character, C, and simultaneously the start and end positions for embroidering the area are specified in different positions belonging to two sub-areas of the area, respectively, which are located at end portions of the area (i.e., end sub-areas of the area), the data producing means may determine the order of embroidering of the sub-areas such that the embroidering begins with the sub-area to which the start position belongs, proceeds in the order of location or position of the sub-areas in the area, and ends with the sub-area to which the end position belongs.
However, an area may have a junction or a branch as the area E shown in FIG. 36. The block numbered eight of the area E is a junction block from which four branches extend outward. There will be described the case where the production of position-related data for embroidering the area E of FIG. 36, for example, by reference to FIG. 37.
Specifically, first, the data producing means determines the block numbered thirteen to which the start position indicated at Ps in FIG. 37, i.e., position numbered twenty five belongs, as the first block to be embroidered, and the blocks numbered fourteen and fifteen as the second and third blocks to be embroidered. The block numbered fifteen is one of the four adjacent blocks of the junction block, numbered eight. The junction block, however, is not determined as the fourth block to be embroidered. One of the three adjacent blocks of the junction block different from the block numbered fifteen, is selected, and a block which is the end block of a branch to which the selected block belongs, is determined as the fourth block to be embroidered. If the end block, numbered four, is determined as the fourth block, the blocks numbered three, two, and one are determined as the fifth, sixth, and seventh blocks to be embroidered. If, in this case, the blocks numbered one, two, three, and four are determined as the fourth, fifth, sixth, and seventh block to be embroidered, the continuous thread passes over the stitches formed in the blocks numbered four, three, two, and one when the thread is returned from the end block to the junction block. This leads to deteriorating the quality of embroidery of the area E.
It is desired that the production of stitch position-related data or stitch position data be automated to as high an extent as possible. That is, it is required that the load applied to the operator for the data production be reduced to as low an extent as possible and the time needed for the data production be minimized. However, none of the above identified apparatus are sufficiently satisfactory since those apparatus do not provide a sufficient degree of automation of the data production.